1. Field of the Invention
This invention relates to a variable capacity swash plate compressor, and more particularly to a variable capacity swash plate compressor having a construction which improves the slidability between a retainer for retaining shoes and a retainer support plate supporting the retainer.
2. Description of the Prior Art
FIG. 1 shows the whole arrangement of a conventional variable capacity swash plate compressor.
The conventional variable capacity swash plate compressor includes a drive shaft 105, a thrust flange 140 rigidly fitted on the drive shaft 105, for rotation in unison with the drive shaft 105, a swash plate 110 which is axially movably mounted on the drive shaft 105 via a hinge ball 109, for rotation in unison with the thrust flange 140, a plurality of pistons 107 slidably received in a plurality of cylinder bores 106, respectively, a plurality of shoes 150 arranged on a sliding surface 110a of the swash plate 110, for relative rotation with respect to the swash plate 110 according to the rotation of the drive shaft 105, a retainer 153 retaining the shoes 150, and a plurality of connecting rods 111.
Each connecting rod 111 has one end 111a, spherical in shape, slidably held in a corresponding one of the shoes 150, for relative rotation with respect to the corresponding shoe 150, and the other end 111b secured to the piston 107.
FIG. 2 is a view of the swash plate 110 taken from a rear side of the compressor.
The retainer 153 has its outer peripheral portion formed with a plurality of broken semi-annular portions 160 along its circumference through each of which a protruding portion 150a of each shoe 150 protrudes toward the piston 107. The retainer 153 is supported or held by a retainer support plate 155 which is fixed to a boss 110a of the swash plate 110 by bolts 154, such that the retainer 153 can perform relative rotation with respect to the retainer support plate 155.
Torque of an engine, not shown, installed on an automotive vehicle, not shown, is transmitted to the drive shaft 105 to rotate the same. The torque of the drive shaft 105 is transmitted from the thrust flange 140 to the swash plate 110 via a linkage 141 to cause rotation of the swash plate 110.
The rotation of the swash plate 110 causes relative rotation of each shoe 150 on the sliding surface 110a of the swash plate 110 with respect to the swash plate 110, whereby the torque transmitted from the swash plate 110 is converted into reciprocating motion of the piston 107. As each piston 107 reciprocates within the cylinder bore 106, the volume of a compression chamber within the cylinder bore 106 changes, whereby suction, compression and delivery of refrigerant gas are carried out sequentially. The inclination of the swash plate 110 varies with pressure within a crankcase 108 in which the swash plate 110 is received, so that high-pressure refrigerant gas is delivered in an amount or volume corresponding to an inclination of the swash plate 110.
The retainer 153 performs relative rotation (or sliding) with respect to the swash plate 110 while receiving tensile forces of pistons 107 in the suction stroke for drawing refrigerant gas into compression chambers, at corresponding portions of the retainer 153. The retainer support plate 155 supports or holds the retainer 153 in a state held in surface contact with a whole central portion of one face 153a of the retainer 153. Therefore, the conventional variable capacity swash plate compressor suffers from the inconvenience that when conditions of lubrication get worse, the sliding contact portions of the retainer 153 and the retainer support plate 155 are abraded, and untoward noises are produced.